The answer is likely yes, but it would be minuscule because residential runoff represents such a small amount of the lake's total phosphorous loading, local watershed coordinator Laura Walker said.

Walker said she feels the issue is better addressed through education and voluntary compliance than a statewide or local ban.

More local lawn care businesses and stores that sell fertilizer now carry phosphorous-free fertilizers since customers started requesting it, Walker said. This is good because data gathered during the last four years show many lawns in the watershed do not need phosphorous at all, she said.

The Grand Lake/Wabash Watershed Alliance four years ago started a residential lawn sampling program that shows homeowners how to collect lawn soil samples so they know what is needed on their lawns. The watershed group, the non-profit Lake Improvement Association and a local agronomics company subsidize the cost so that homeowners only pay $5 instead of $20 for the testing. Homeowners receive a report so then they apply the proper nutrients.

Lawn fertilizer is formulated using percentages of nitrogen, phosphorous and potassium. These three numbers typically are on the outside of the fertilizer bag.

Most lawns don't need phosphorous because clippings left on the ground produce phosphorous, Walker said. The only time it is needed is if a homeowner is establishing a brand new lawn because phosphorous builds strong roots, she added. Nitrogen is the main nutrient that gives a lawn its green color.

Lake resident Bill Ringo supports a local ban on lawn fertilizers containing phosphorous because any reduction in phosphorous no matter how small would help.

About five years ago Ringo and other LIA members asked Mercer County Commissioners to enact such a ban. Both commissioners and county health department officials told him they didn't have the jurisdiction. John Leutz, senior policy analyst with the County Commissioners Association of Ohio, agreed, adding that a city government would be in a better position to enact such a ban because cities are not solely governed by Ohio Revised Code.

The Michigan ban on phosphorous excludes farms, golf courses, new lawns and homeowners with soil tests that prove their lawns need phosphorus. The counties of Oakland, Macomb and Wayne in Michigan already had bans in place that were enacted locally.

Other Great Lakes states that restrict phosphorus fertilizers are Minnesota, Wisconsin, New York and Illinois.

The only mandated restrictions on phosphorous locally are for the 300-plus livestock farmers in the Grand Lake Watershed. Twenty new manure rules from the state soon will require farmers to have nutrient management plans, conduct soil tests to determine if their ground can accept phosphorous-containing manure and install more waste storage structures so they don't spread manure during the winter. Manure is more prone to runoff when the ground is frozen and/or snow covered.

Walker said farmers she has talked to are "aggravated" because they receive most of the blame for Grand Lake's condition. The lake has suffered for years from massive algae blooms caused by too much phosphorous in the water. Walker said farmers don't believe the entire watershed, lawns included, should be made a phosphorous-free zone.

"You need some phosphorous to get crops and a lawn growing," Walker said.

State Sen. Keith Faber, R-Celina, said he would not support legislation banning lawn fertilizers containing phosphorous in Ohio without science showing it would benefit the Great Lakes or Grand Lake. Scientific data gathered locally shows most of the nutrient loading comes from farmland, he noted.

"I've never seen a proposed bill on this topic or had any discussions in committees or seen any research on the topic," he said.

Speaking specifically to Grand Lake, Faber said, "The lake is a multifaceted problem that will take multifaceted solutions to solve, but that does not mean you impose legislation that has very little benefit."

Faber said he thinks home-owners in the watershed "get it" and are acting accordingly by buying fertilizers with no phosphorous.

"We shouldn't rely on broad-sweeping regulatory mechanisms if you can get there in a more narrowly-focused and less costly manner," he said. "The goal is achieving compliance."